1. Field of the Invention
The present invention pertains to an improved arrangement of gearing and clutches in a multispeed, reversible, constant mesh gear transmission having plural clutches engageable and disengageable under load.
2. Background Art
Multispeed reversible gear transmissions of the constant mesh and so-called power shiftable type are widely used in heavy duty vehicular applications and construction equipment. Such applications of gear transmissions require a wide range of speed ratios between the transmission input shaft and output shaft in both forward and reverse directions of rotation in order to provide satisfactory vehicle movement under widely varying load conditions and to optimize the vehicle engine operating speed range for maximum efficiency and power output. Accordingly, a number of transmission designs have been developed in an effort to provide a compact transmission unit having a maximum number of input to output gear ratios in a forward direction as well as reverse direction of rotation of the output shaft with respect to the input shaft.
In the art of constant mesh gear transmissions for heavy duty vehicles and construction equipment it is desirable to provide arrangements of the gearing and rotating shafts of transmissions having different speed ratio capabilities which are adaptable to be used in the same transmission housing and which use a relatively large number of common parts to reduce manufacturing costs and to improve serviceability.
Moreover, the continued effort to develop various types of equipment which operate satisfactorily with smaller engines for economy of operation has necessitated the development of transmissions having a greater number of gear speed ratios in both forward and reverse direction to provide satisfactory equipment performance. It is, of course, desirable to be able to maximize the number of gear ratios while at the same time minimizing the number of gears and clutches required to provide speed and direction change of the transmission output shaft with respect to the input shaft.